1 /* $NetBSD: ffs_alloc.c,v 1.14 2004/06/20 22:20:18 jmc Exp $ */ 2 /* From: NetBSD: ffs_alloc.c,v 1.50 2001/09/06 02:16:01 lukem Exp */ 3 4 /* 5 * Copyright (c) 2002 Networks Associates Technology, Inc. 6 * All rights reserved. 7 * 8 * This software was developed for the FreeBSD Project by Marshall 9 * Kirk McKusick and Network Associates Laboratories, the Security 10 * Research Division of Network Associates, Inc. under DARPA/SPAWAR 11 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS 12 * research program 13 * 14 * Copyright (c) 1982, 1986, 1989, 1993 15 * The Regents of the University of California. All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 3. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)ffs_alloc.c 8.19 (Berkeley) 7/13/95 42 */ 43 44 #include <sys/cdefs.h> 45 __FBSDID("$FreeBSD$"); 46 47 #include <sys/param.h> 48 #include <sys/time.h> 49 50 #include <errno.h> 51 52 #include "makefs.h" 53 54 #include <ufs/ufs/dinode.h> 55 #include <ufs/ffs/fs.h> 56 57 #include "ffs/ufs_bswap.h" 58 #include "ffs/buf.h" 59 #include "ffs/ufs_inode.h" 60 #include "ffs/ffs_extern.h" 61 62 static int scanc(u_int, const u_char *, const u_char *, int); 63 64 static daddr_t ffs_alloccg(struct inode *, int, daddr_t, int); 65 static daddr_t ffs_alloccgblk(struct inode *, struct buf *, daddr_t); 66 static daddr_t ffs_hashalloc(struct inode *, int, daddr_t, int, 67 daddr_t (*)(struct inode *, int, daddr_t, int)); 68 static int32_t ffs_mapsearch(struct fs *, struct cg *, daddr_t, int); 69 70 /* 71 * Allocate a block in the file system. 72 * 73 * The size of the requested block is given, which must be some 74 * multiple of fs_fsize and <= fs_bsize. 75 * A preference may be optionally specified. If a preference is given 76 * the following hierarchy is used to allocate a block: 77 * 1) allocate the requested block. 78 * 2) allocate a rotationally optimal block in the same cylinder. 79 * 3) allocate a block in the same cylinder group. 80 * 4) quadradically rehash into other cylinder groups, until an 81 * available block is located. 82 * If no block preference is given the following hierarchy is used 83 * to allocate a block: 84 * 1) allocate a block in the cylinder group that contains the 85 * inode for the file. 86 * 2) quadradically rehash into other cylinder groups, until an 87 * available block is located. 88 */ 89 int 90 ffs_alloc(struct inode *ip, daddr_t lbn, daddr_t bpref, int size, 91 daddr_t *bnp) 92 { 93 struct fs *fs = ip->i_fs; 94 daddr_t bno; 95 int cg; 96 97 *bnp = 0; 98 if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0) { 99 errx(1, "ffs_alloc: bad size: bsize %d size %d", 100 fs->fs_bsize, size); 101 } 102 if (size == fs->fs_bsize && fs->fs_cstotal.cs_nbfree == 0) 103 goto nospace; 104 if (bpref >= fs->fs_size) 105 bpref = 0; 106 if (bpref == 0) 107 cg = ino_to_cg(fs, ip->i_number); 108 else 109 cg = dtog(fs, bpref); 110 bno = ffs_hashalloc(ip, cg, bpref, size, ffs_alloccg); 111 if (bno > 0) { 112 if (ip->i_fs->fs_magic == FS_UFS1_MAGIC) 113 ip->i_ffs1_blocks += size / DEV_BSIZE; 114 else 115 ip->i_ffs2_blocks += size / DEV_BSIZE; 116 *bnp = bno; 117 return (0); 118 } 119 nospace: 120 return (ENOSPC); 121 } 122 123 /* 124 * Select the desired position for the next block in a file. The file is 125 * logically divided into sections. The first section is composed of the 126 * direct blocks. Each additional section contains fs_maxbpg blocks. 127 * 128 * If no blocks have been allocated in the first section, the policy is to 129 * request a block in the same cylinder group as the inode that describes 130 * the file. If no blocks have been allocated in any other section, the 131 * policy is to place the section in a cylinder group with a greater than 132 * average number of free blocks. An appropriate cylinder group is found 133 * by using a rotor that sweeps the cylinder groups. When a new group of 134 * blocks is needed, the sweep begins in the cylinder group following the 135 * cylinder group from which the previous allocation was made. The sweep 136 * continues until a cylinder group with greater than the average number 137 * of free blocks is found. If the allocation is for the first block in an 138 * indirect block, the information on the previous allocation is unavailable; 139 * here a best guess is made based upon the logical block number being 140 * allocated. 141 * 142 * If a section is already partially allocated, the policy is to 143 * contiguously allocate fs_maxcontig blocks. The end of one of these 144 * contiguous blocks and the beginning of the next is physically separated 145 * so that the disk head will be in transit between them for at least 146 * fs_rotdelay milliseconds. This is to allow time for the processor to 147 * schedule another I/O transfer. 148 */ 149 /* XXX ondisk32 */ 150 daddr_t 151 ffs_blkpref_ufs1(struct inode *ip, daddr_t lbn, int indx, int32_t *bap) 152 { 153 struct fs *fs; 154 int cg; 155 int avgbfree, startcg; 156 157 fs = ip->i_fs; 158 if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) { 159 if (lbn < NDADDR + NINDIR(fs)) { 160 cg = ino_to_cg(fs, ip->i_number); 161 return (fs->fs_fpg * cg + fs->fs_frag); 162 } 163 /* 164 * Find a cylinder with greater than average number of 165 * unused data blocks. 166 */ 167 if (indx == 0 || bap[indx - 1] == 0) 168 startcg = 169 ino_to_cg(fs, ip->i_number) + lbn / fs->fs_maxbpg; 170 else 171 startcg = dtog(fs, 172 ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + 1); 173 startcg %= fs->fs_ncg; 174 avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg; 175 for (cg = startcg; cg < fs->fs_ncg; cg++) 176 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) 177 return (fs->fs_fpg * cg + fs->fs_frag); 178 for (cg = 0; cg <= startcg; cg++) 179 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) 180 return (fs->fs_fpg * cg + fs->fs_frag); 181 return (0); 182 } 183 /* 184 * We just always try to lay things out contiguously. 185 */ 186 return ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag; 187 } 188 189 daddr_t 190 ffs_blkpref_ufs2(ip, lbn, indx, bap) 191 struct inode *ip; 192 daddr_t lbn; 193 int indx; 194 int64_t *bap; 195 { 196 struct fs *fs; 197 int cg; 198 int avgbfree, startcg; 199 200 fs = ip->i_fs; 201 if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) { 202 if (lbn < NDADDR + NINDIR(fs)) { 203 cg = ino_to_cg(fs, ip->i_number); 204 return (fs->fs_fpg * cg + fs->fs_frag); 205 } 206 /* 207 * Find a cylinder with greater than average number of 208 * unused data blocks. 209 */ 210 if (indx == 0 || bap[indx - 1] == 0) 211 startcg = 212 ino_to_cg(fs, ip->i_number) + lbn / fs->fs_maxbpg; 213 else 214 startcg = dtog(fs, 215 ufs_rw64(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + 1); 216 startcg %= fs->fs_ncg; 217 avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg; 218 for (cg = startcg; cg < fs->fs_ncg; cg++) 219 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) { 220 return (fs->fs_fpg * cg + fs->fs_frag); 221 } 222 for (cg = 0; cg < startcg; cg++) 223 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) { 224 return (fs->fs_fpg * cg + fs->fs_frag); 225 } 226 return (0); 227 } 228 /* 229 * We just always try to lay things out contiguously. 230 */ 231 return ufs_rw64(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag; 232 } 233 234 /* 235 * Implement the cylinder overflow algorithm. 236 * 237 * The policy implemented by this algorithm is: 238 * 1) allocate the block in its requested cylinder group. 239 * 2) quadradically rehash on the cylinder group number. 240 * 3) brute force search for a free block. 241 * 242 * `size': size for data blocks, mode for inodes 243 */ 244 /*VARARGS5*/ 245 static daddr_t 246 ffs_hashalloc(struct inode *ip, int cg, daddr_t pref, int size, 247 daddr_t (*allocator)(struct inode *, int, daddr_t, int)) 248 { 249 struct fs *fs; 250 daddr_t result; 251 int i, icg = cg; 252 253 fs = ip->i_fs; 254 /* 255 * 1: preferred cylinder group 256 */ 257 result = (*allocator)(ip, cg, pref, size); 258 if (result) 259 return (result); 260 /* 261 * 2: quadratic rehash 262 */ 263 for (i = 1; i < fs->fs_ncg; i *= 2) { 264 cg += i; 265 if (cg >= fs->fs_ncg) 266 cg -= fs->fs_ncg; 267 result = (*allocator)(ip, cg, 0, size); 268 if (result) 269 return (result); 270 } 271 /* 272 * 3: brute force search 273 * Note that we start at i == 2, since 0 was checked initially, 274 * and 1 is always checked in the quadratic rehash. 275 */ 276 cg = (icg + 2) % fs->fs_ncg; 277 for (i = 2; i < fs->fs_ncg; i++) { 278 result = (*allocator)(ip, cg, 0, size); 279 if (result) 280 return (result); 281 cg++; 282 if (cg == fs->fs_ncg) 283 cg = 0; 284 } 285 return (0); 286 } 287 288 /* 289 * Determine whether a block can be allocated. 290 * 291 * Check to see if a block of the appropriate size is available, 292 * and if it is, allocate it. 293 */ 294 static daddr_t 295 ffs_alloccg(struct inode *ip, int cg, daddr_t bpref, int size) 296 { 297 struct cg *cgp; 298 struct buf *bp; 299 daddr_t bno, blkno; 300 int error, frags, allocsiz, i; 301 struct fs *fs = ip->i_fs; 302 const int needswap = UFS_FSNEEDSWAP(fs); 303 304 if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize) 305 return (0); 306 error = bread(ip->i_fd, ip->i_fs, fsbtodb(fs, cgtod(fs, cg)), 307 (int)fs->fs_cgsize, &bp); 308 if (error) { 309 brelse(bp); 310 return (0); 311 } 312 cgp = (struct cg *)bp->b_data; 313 if (!cg_chkmagic_swap(cgp, needswap) || 314 (cgp->cg_cs.cs_nbfree == 0 && size == fs->fs_bsize)) { 315 brelse(bp); 316 return (0); 317 } 318 if (size == fs->fs_bsize) { 319 bno = ffs_alloccgblk(ip, bp, bpref); 320 bdwrite(bp); 321 return (bno); 322 } 323 /* 324 * check to see if any fragments are already available 325 * allocsiz is the size which will be allocated, hacking 326 * it down to a smaller size if necessary 327 */ 328 frags = numfrags(fs, size); 329 for (allocsiz = frags; allocsiz < fs->fs_frag; allocsiz++) 330 if (cgp->cg_frsum[allocsiz] != 0) 331 break; 332 if (allocsiz == fs->fs_frag) { 333 /* 334 * no fragments were available, so a block will be 335 * allocated, and hacked up 336 */ 337 if (cgp->cg_cs.cs_nbfree == 0) { 338 brelse(bp); 339 return (0); 340 } 341 bno = ffs_alloccgblk(ip, bp, bpref); 342 bpref = dtogd(fs, bno); 343 for (i = frags; i < fs->fs_frag; i++) 344 setbit(cg_blksfree_swap(cgp, needswap), bpref + i); 345 i = fs->fs_frag - frags; 346 ufs_add32(cgp->cg_cs.cs_nffree, i, needswap); 347 fs->fs_cstotal.cs_nffree += i; 348 fs->fs_cs(fs, cg).cs_nffree += i; 349 fs->fs_fmod = 1; 350 ufs_add32(cgp->cg_frsum[i], 1, needswap); 351 bdwrite(bp); 352 return (bno); 353 } 354 bno = ffs_mapsearch(fs, cgp, bpref, allocsiz); 355 for (i = 0; i < frags; i++) 356 clrbit(cg_blksfree_swap(cgp, needswap), bno + i); 357 ufs_add32(cgp->cg_cs.cs_nffree, -frags, needswap); 358 fs->fs_cstotal.cs_nffree -= frags; 359 fs->fs_cs(fs, cg).cs_nffree -= frags; 360 fs->fs_fmod = 1; 361 ufs_add32(cgp->cg_frsum[allocsiz], -1, needswap); 362 if (frags != allocsiz) 363 ufs_add32(cgp->cg_frsum[allocsiz - frags], 1, needswap); 364 blkno = cg * fs->fs_fpg + bno; 365 bdwrite(bp); 366 return blkno; 367 } 368 369 /* 370 * Allocate a block in a cylinder group. 371 * 372 * This algorithm implements the following policy: 373 * 1) allocate the requested block. 374 * 2) allocate a rotationally optimal block in the same cylinder. 375 * 3) allocate the next available block on the block rotor for the 376 * specified cylinder group. 377 * Note that this routine only allocates fs_bsize blocks; these 378 * blocks may be fragmented by the routine that allocates them. 379 */ 380 static daddr_t 381 ffs_alloccgblk(struct inode *ip, struct buf *bp, daddr_t bpref) 382 { 383 struct cg *cgp; 384 daddr_t blkno; 385 int32_t bno; 386 struct fs *fs = ip->i_fs; 387 const int needswap = UFS_FSNEEDSWAP(fs); 388 u_int8_t *blksfree; 389 390 cgp = (struct cg *)bp->b_data; 391 blksfree = cg_blksfree_swap(cgp, needswap); 392 if (bpref == 0 || dtog(fs, bpref) != ufs_rw32(cgp->cg_cgx, needswap)) { 393 bpref = ufs_rw32(cgp->cg_rotor, needswap); 394 } else { 395 bpref = blknum(fs, bpref); 396 bno = dtogd(fs, bpref); 397 /* 398 * if the requested block is available, use it 399 */ 400 if (ffs_isblock(fs, blksfree, fragstoblks(fs, bno))) 401 goto gotit; 402 } 403 /* 404 * Take the next available one in this cylinder group. 405 */ 406 bno = ffs_mapsearch(fs, cgp, bpref, (int)fs->fs_frag); 407 if (bno < 0) 408 return (0); 409 cgp->cg_rotor = ufs_rw32(bno, needswap); 410 gotit: 411 blkno = fragstoblks(fs, bno); 412 ffs_clrblock(fs, blksfree, (long)blkno); 413 ffs_clusteracct(fs, cgp, blkno, -1); 414 ufs_add32(cgp->cg_cs.cs_nbfree, -1, needswap); 415 fs->fs_cstotal.cs_nbfree--; 416 fs->fs_cs(fs, ufs_rw32(cgp->cg_cgx, needswap)).cs_nbfree--; 417 fs->fs_fmod = 1; 418 blkno = ufs_rw32(cgp->cg_cgx, needswap) * fs->fs_fpg + bno; 419 return (blkno); 420 } 421 422 /* 423 * Free a block or fragment. 424 * 425 * The specified block or fragment is placed back in the 426 * free map. If a fragment is deallocated, a possible 427 * block reassembly is checked. 428 */ 429 void 430 ffs_blkfree(struct inode *ip, daddr_t bno, long size) 431 { 432 struct cg *cgp; 433 struct buf *bp; 434 int32_t fragno, cgbno; 435 int i, error, cg, blk, frags, bbase; 436 struct fs *fs = ip->i_fs; 437 const int needswap = UFS_FSNEEDSWAP(fs); 438 439 if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0 || 440 fragnum(fs, bno) + numfrags(fs, size) > fs->fs_frag) { 441 errx(1, "blkfree: bad size: bno %lld bsize %d size %ld", 442 (long long)bno, fs->fs_bsize, size); 443 } 444 cg = dtog(fs, bno); 445 if (bno >= fs->fs_size) { 446 warnx("bad block %lld, ino %d", (long long)bno, ip->i_number); 447 return; 448 } 449 error = bread(ip->i_fd, ip->i_fs, fsbtodb(fs, cgtod(fs, cg)), 450 (int)fs->fs_cgsize, &bp); 451 if (error) { 452 brelse(bp); 453 return; 454 } 455 cgp = (struct cg *)bp->b_data; 456 if (!cg_chkmagic_swap(cgp, needswap)) { 457 brelse(bp); 458 return; 459 } 460 cgbno = dtogd(fs, bno); 461 if (size == fs->fs_bsize) { 462 fragno = fragstoblks(fs, cgbno); 463 if (!ffs_isfreeblock(fs, cg_blksfree_swap(cgp, needswap), fragno)) { 464 errx(1, "blkfree: freeing free block %lld", 465 (long long)bno); 466 } 467 ffs_setblock(fs, cg_blksfree_swap(cgp, needswap), fragno); 468 ffs_clusteracct(fs, cgp, fragno, 1); 469 ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap); 470 fs->fs_cstotal.cs_nbfree++; 471 fs->fs_cs(fs, cg).cs_nbfree++; 472 } else { 473 bbase = cgbno - fragnum(fs, cgbno); 474 /* 475 * decrement the counts associated with the old frags 476 */ 477 blk = blkmap(fs, cg_blksfree_swap(cgp, needswap), bbase); 478 ffs_fragacct_swap(fs, blk, cgp->cg_frsum, -1, needswap); 479 /* 480 * deallocate the fragment 481 */ 482 frags = numfrags(fs, size); 483 for (i = 0; i < frags; i++) { 484 if (isset(cg_blksfree_swap(cgp, needswap), cgbno + i)) { 485 errx(1, "blkfree: freeing free frag: block %lld", 486 (long long)(cgbno + i)); 487 } 488 setbit(cg_blksfree_swap(cgp, needswap), cgbno + i); 489 } 490 ufs_add32(cgp->cg_cs.cs_nffree, i, needswap); 491 fs->fs_cstotal.cs_nffree += i; 492 fs->fs_cs(fs, cg).cs_nffree += i; 493 /* 494 * add back in counts associated with the new frags 495 */ 496 blk = blkmap(fs, cg_blksfree_swap(cgp, needswap), bbase); 497 ffs_fragacct_swap(fs, blk, cgp->cg_frsum, 1, needswap); 498 /* 499 * if a complete block has been reassembled, account for it 500 */ 501 fragno = fragstoblks(fs, bbase); 502 if (ffs_isblock(fs, cg_blksfree_swap(cgp, needswap), fragno)) { 503 ufs_add32(cgp->cg_cs.cs_nffree, -fs->fs_frag, needswap); 504 fs->fs_cstotal.cs_nffree -= fs->fs_frag; 505 fs->fs_cs(fs, cg).cs_nffree -= fs->fs_frag; 506 ffs_clusteracct(fs, cgp, fragno, 1); 507 ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap); 508 fs->fs_cstotal.cs_nbfree++; 509 fs->fs_cs(fs, cg).cs_nbfree++; 510 } 511 } 512 fs->fs_fmod = 1; 513 bdwrite(bp); 514 } 515 516 517 static int 518 scanc(u_int size, const u_char *cp, const u_char table[], int mask) 519 { 520 const u_char *end = &cp[size]; 521 522 while (cp < end && (table[*cp] & mask) == 0) 523 cp++; 524 return (end - cp); 525 } 526 527 /* 528 * Find a block of the specified size in the specified cylinder group. 529 * 530 * It is a panic if a request is made to find a block if none are 531 * available. 532 */ 533 static int32_t 534 ffs_mapsearch(struct fs *fs, struct cg *cgp, daddr_t bpref, int allocsiz) 535 { 536 int32_t bno; 537 int start, len, loc, i; 538 int blk, field, subfield, pos; 539 int ostart, olen; 540 const int needswap = UFS_FSNEEDSWAP(fs); 541 542 /* 543 * find the fragment by searching through the free block 544 * map for an appropriate bit pattern 545 */ 546 if (bpref) 547 start = dtogd(fs, bpref) / NBBY; 548 else 549 start = ufs_rw32(cgp->cg_frotor, needswap) / NBBY; 550 len = howmany(fs->fs_fpg, NBBY) - start; 551 ostart = start; 552 olen = len; 553 loc = scanc((u_int)len, 554 (const u_char *)&cg_blksfree_swap(cgp, needswap)[start], 555 (const u_char *)fragtbl[fs->fs_frag], 556 (1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); 557 if (loc == 0) { 558 len = start + 1; 559 start = 0; 560 loc = scanc((u_int)len, 561 (const u_char *)&cg_blksfree_swap(cgp, needswap)[0], 562 (const u_char *)fragtbl[fs->fs_frag], 563 (1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); 564 if (loc == 0) { 565 errx(1, 566 "ffs_alloccg: map corrupted: start %d len %d offset %d %ld", 567 ostart, olen, 568 ufs_rw32(cgp->cg_freeoff, needswap), 569 (long)cg_blksfree_swap(cgp, needswap) - (long)cgp); 570 /* NOTREACHED */ 571 } 572 } 573 bno = (start + len - loc) * NBBY; 574 cgp->cg_frotor = ufs_rw32(bno, needswap); 575 /* 576 * found the byte in the map 577 * sift through the bits to find the selected frag 578 */ 579 for (i = bno + NBBY; bno < i; bno += fs->fs_frag) { 580 blk = blkmap(fs, cg_blksfree_swap(cgp, needswap), bno); 581 blk <<= 1; 582 field = around[allocsiz]; 583 subfield = inside[allocsiz]; 584 for (pos = 0; pos <= fs->fs_frag - allocsiz; pos++) { 585 if ((blk & field) == subfield) 586 return (bno + pos); 587 field <<= 1; 588 subfield <<= 1; 589 } 590 } 591 errx(1, "ffs_alloccg: block not in map: bno %lld", (long long)bno); 592 return (-1); 593 } 594 595 /* 596 * Update the cluster map because of an allocation or free. 597 * 598 * Cnt == 1 means free; cnt == -1 means allocating. 599 */ 600 void 601 ffs_clusteracct(struct fs *fs, struct cg *cgp, int32_t blkno, int cnt) 602 { 603 int32_t *sump; 604 int32_t *lp; 605 u_char *freemapp, *mapp; 606 int i, start, end, forw, back, map, bit; 607 const int needswap = UFS_FSNEEDSWAP(fs); 608 609 if (fs->fs_contigsumsize <= 0) 610 return; 611 freemapp = cg_clustersfree_swap(cgp, needswap); 612 sump = cg_clustersum_swap(cgp, needswap); 613 /* 614 * Allocate or clear the actual block. 615 */ 616 if (cnt > 0) 617 setbit(freemapp, blkno); 618 else 619 clrbit(freemapp, blkno); 620 /* 621 * Find the size of the cluster going forward. 622 */ 623 start = blkno + 1; 624 end = start + fs->fs_contigsumsize; 625 if (end >= ufs_rw32(cgp->cg_nclusterblks, needswap)) 626 end = ufs_rw32(cgp->cg_nclusterblks, needswap); 627 mapp = &freemapp[start / NBBY]; 628 map = *mapp++; 629 bit = 1 << (start % NBBY); 630 for (i = start; i < end; i++) { 631 if ((map & bit) == 0) 632 break; 633 if ((i & (NBBY - 1)) != (NBBY - 1)) { 634 bit <<= 1; 635 } else { 636 map = *mapp++; 637 bit = 1; 638 } 639 } 640 forw = i - start; 641 /* 642 * Find the size of the cluster going backward. 643 */ 644 start = blkno - 1; 645 end = start - fs->fs_contigsumsize; 646 if (end < 0) 647 end = -1; 648 mapp = &freemapp[start / NBBY]; 649 map = *mapp--; 650 bit = 1 << (start % NBBY); 651 for (i = start; i > end; i--) { 652 if ((map & bit) == 0) 653 break; 654 if ((i & (NBBY - 1)) != 0) { 655 bit >>= 1; 656 } else { 657 map = *mapp--; 658 bit = 1 << (NBBY - 1); 659 } 660 } 661 back = start - i; 662 /* 663 * Account for old cluster and the possibly new forward and 664 * back clusters. 665 */ 666 i = back + forw + 1; 667 if (i > fs->fs_contigsumsize) 668 i = fs->fs_contigsumsize; 669 ufs_add32(sump[i], cnt, needswap); 670 if (back > 0) 671 ufs_add32(sump[back], -cnt, needswap); 672 if (forw > 0) 673 ufs_add32(sump[forw], -cnt, needswap); 674 675 /* 676 * Update cluster summary information. 677 */ 678 lp = &sump[fs->fs_contigsumsize]; 679 for (i = fs->fs_contigsumsize; i > 0; i--) 680 if (ufs_rw32(*lp--, needswap) > 0) 681 break; 682 fs->fs_maxcluster[ufs_rw32(cgp->cg_cgx, needswap)] = i; 683 } 684